This invention relates to a four-cycle engine and more particularly to an improved valve and combustion chamber arrangement for such an engine.
As is well known, the performance of a four-cycle engine may be improved through the use of multiple intake and/or exhaust valves. By using multiple valves, the valve area communicating with each chamber may be increased. The use of multiple valves permits an increased valve area without increasing the inertia of individual valve components as would be true if merely larger valves were employed. Hence, higher engine speeds may be attained through the use of multiple valves. In addition, the use of multiple valves permits a greater valve area in a given combustion chamber area. The use of multiple valves, however, does present some difficulties. As a number of valves in a given chamber is increased, it is necessary to place the valves so that they do not interfere with each other during their opening and closing movement. In addition, the use of a greater number of valves may complicate the actuating system for the valves.
It is, therefore, a principal object of this invention to provide an improved and simplified multiple valve arrangement for an internal combustion engine.
It is a further object of the invention to provide a multiple valve arrangement wherein more than one valve is operated by the same cam shaft.
It is desirable to provide a direct valve actuation wherein the cam lobes act directly on the valves to operate them. Such an arrangement reduces the complexity of the valve train and further permits higher speeds due to the lower inertia. However, where multiple valves are employed, and particularly if a greater number of valves than two for either the intake or exhaust are employed, it has been difficult if not impossible to provide such direct action on all valves.
It is, therefore, yet a further object of this invention to provide a combustion chamber for an engine that permits the use of multiple, directly actuated valves.